Fire resistant resin composition and electrical wire having fire resistant covering

ABSTRACT

A fire resistant resin composition, a method of making the fire resistant resin composition and an electrical wire comprising the fire resistant resin composition are provided. The fire resistant composition includes a halogen-free propylene resin containing propylene as its main monomer component, a halogen-free styrene-based thermoplastic elastomeric resin modified with an unsaturated carboxylic acid or a derivative of such an acid, and a fire resistant metal hydroxide.

INCORPORATION BY REFERENCE

[0001] This is a Continuation of application Ser. No. 10/012,517 filedDec. 12, 2001. The entire disclosure of the prior application is herebyincorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of Invention

[0003] This invention relates to a fire resistant or non-flammable resincomposition, and a coated electrical wire including an electricalconductor and a covering made of the composition.

[0004] 2. Description of Related Art

[0005] Polyvinyl chloride, which has superior flame resistance, isconventionally used as a coating material for electrical wire that isused in vehicles or electrical/electronic equipment. To obtain requiredcharacteristics in the wire, such as mechanical properties includingwear resistance and tensile strength, along with flexibility andprocessability, additives such as plasticizers or stabilizers are addedto the polyvinyl chloride in varying amounts.

[0006] Polyvinyl chloride has low flammability. However, it containshalogen, so when a vehicle or electrical/electronic equipment employingwire coated with polyvinyl chloride is burned, a harmful halogen gas isreleased into the atmosphere, thus causing environmental pollution.

[0007] In recent years, research has been conducted on fire resistantresin compositions that do not contain halogen. For example, ahalogen-free resin composition disclosed in JP-A-5-301996 contains amixture of a polyolefin and a high-density polyethylene, with a metalhydroxide added to the mixture as a fire resistant agent.

[0008] Another halogen-free fire resistant resin composition isdisclosed in JP-B-7-110912. This composition contains a mixture of athermoplastic elastomer and a polyolefin having a low crystallisability,with an inorganic fire resistant agent added to the mixture.

[0009] The electrical wire disclosed in JP-B-7-78518 includes aconductor covered with a cross-linked resin composition containing amixture of a polyolefin having a melting point of not less than 120° C.and a carboxylic acid-modified polymer, with a surface-treated magnesiumhydroxide added to the mixture.

[0010] However, in the case of the composition disclosed inJP-A-5-301996, it is necessary to add a large amount of metal hydroxideto the mixture of the polyolefin and the high-density polyethylene toachieve sufficient fire resistance, so that the composition isself-extinguishing. Due to the quantity of metal hydroxide, thecomposition has poor mechanical strength demonstrated by low wearresistance and tensile strength.

[0011] It is possible to increase the content of the high-densitypolyethylene, which is crystallizable and has comparatively highhardness, to improve the mechanical characteristics of such acomposition. However, if the quantity of high-density polyethylene isincreased, the composition has a small amount of non-crystallinematerial, and it is only possible to add small amounts of the fireresistant agent to the mixture. Consequently, the composition hasreduced fire resistance and flexibility. Further, when the compositionis used as a covering material for electrical wire, it has very poorprocessability and extrusion moldability. Thus, the composition is notsatisfactory.

[0012] In the case of the composition disclosed in JP-B-7-110912, it isalso necessary to add large amounts of an inorganic fire resistant agentto the mixture to achieve a self-extinguishing property. Consequently,as with the composition of JP-A-5-301996, the composition has poormechanical strength as demonstrated by poor wear resistance, tensilestrength, and the like. Further, due to the quantity of the fireresistant agent, the flexibility of the thermoplastic elastomer of thecomposition deteriorates. If the amount of the polyolefin is reduced toimprove the mechanical characteristics of the composition, only a smallamount of a non-crystalline material remains, and only a small amount ofthe fire resistant agent can be added. Consequently, the composition haspoor fire resistance and does not possess the characteristics desired inwire manufacture.

[0013] In the case of the electrical wire of JP-B-7-78518, the resincomposition of the covering is cross-linked. Thus, it is necessary tointroduce a cross-linking step into the process of producing coveredelectrical wire. This additional step increases the number ofmanufacturing steps, in turn increasing the cost of manufacture.

SUMMARY OF THE INVENTION

[0014] Therefore, an object of this invention is to provide a fireresistant resin composition that does not generate halogen gas whenburnt. Another object of this invention is to provide a compositionhaving good mechanical characteristics including wear resistance,tensile strength, tensile elongation, and the like. An additional objectof this invention is to provide a composition having good flexibilityand processability.

[0015] Another object of this invention is to provide an electrical wireincluding an electrical conductor and a coating made of a fire resistantresin composition.

[0016] According to this invention there is provided a fire resistantresin composition including synthetic resin components:

[0017] (a) from about 60 to about 97 parts by weight of a propyleneresin having propylene as its main monomer component by weight, and

[0018] (b) from about 3 to about 40 parts by weight of a styrene-basedthermoplastic elastomeric resin modified with an unsaturated carboxylicacid or a derivative thereof,

[0019] components (a) and (b) being free of halogen, the total amount ofcomponents (a) and (b) being 100 parts by weight and there being noother synthetic resin components included in the composition,

[0020] the composition further including:

[0021] (c) from about 30 to about 200 parts by weight of a fireresistant metal hydroxide per 100 parts by weight of components (a) and(b).

[0022] The invention further provides a method of making the resincomposition by combining and mixing components (a), (b) and (c).Component (b) should preferably be modified with the unsaturatedcarboxylic acid or its derivative, before it is mixed with components(a) and (c).

[0023] The composition of this invention does not contain halogen, so itdoes not generate halogen gas when burned. In addition, the compositionincludes from 60 to 97 parts by weight of propylene resin, an olefinhaving a comparatively high melting point, making it possible to improvethe heat resistance of the resin composition without cross-linking thepolymer.

[0024] The composition contains from 3 to 40 parts by weight of styrenethermoplastic elastomer modified with an unsaturated carboxylic acid orderivative, so the composition is flexible. Further, a strong bondinginterface is formed between the polar metal hydroxide, which acts as afire resistant agent in the composition, and the modified styrenethermoplastic elastomer. Therefore, it is possible to improve mechanicalcharacteristics of the resin composition including wear resistance,tensile strength, and tensile elongation without reducing theflexibility of the composition.

[0025] The resin composition of this invention is highly processable andmoldable because the composition possesses a good balance of mechanicalcharacteristics and flexibility. In addition, because the resincomposition contains from 30 to 200 parts by weight of the metalhydroxide, it provides satisfactory fire resistance.

[0026] In various preferred embodiments, the styrene thermoplasticelastomer modified with the unsaturated carboxylic acid or thederivative thereof is a maleic anhydride-modified styrene thermoplasticelastomer. The metal hydroxide is preferably magnesium hydroxide. Inembodiments where these components are employed, the resin compositionhas excellent mechanical characteristics such as wear resistance.

[0027] The electrical wire of this invention includes a conductor andthe fire resistant resin composition applied to a peripheral surface ofthe conductor. It is preferable that the covering made of the resincomposition has a thickness of from about 0.2 mm to about 0.3 mm.

[0028] These and other features and advantages of this invention aredescribed in, or are apparent from, the following detailed descriptionof various exemplary embodiments of this invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Various exemplary embodiments of this invention will be describedin detail, with reference to the following Figures, wherein:

[0030]FIG. 1 is an electron micrograph of the structure of the resincomposition of Example 11; and

[0031]FIG. 2 is an electron micrograph of the structure of the resincomposition of Comparative Example 10.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0032] The propylene resin of the composition according to thisinvention is a polymer including propylene as its main monomer component(i.e. propylene monomer units constitute at least about 50% by weight ofto the propylene resin). The propylene resin does not include halogen inits molecular structure. The propylene resin can be a homopolymer, arandom copolymer, an alternating copolymer or a block copolymer.

[0033] In various exemplary embodiments according to this invention, thepropylene resin can include polypropylene, a propylene-ethylene blockcopolymer containing propylene as its main monomer component (50% byweight or more), a propylene-ethylene random copolymer, apropylene-butane random copolymer, and a propylene/ethylene-propyleneblock copolymer (i.e., a block copolymer having segments ofpropylene/ethylene polymer and segments of polypropylene). Thesepolymers can be used alone or in combination.

[0034] To improve the processability and extrusion moldability of thepropylene resin, it is preferable that the propylene resin has a meltflow rate (MFR) in the range of from about 0.1 to about 5 g/10 minutesat a temperature of 230° C. and a load of 2.16 kg, as measured inaccordance with JIS K 6758.

[0035] The styrene thermoplastic elastomer of the composition accordingto this invention is a styrene thermoplastic elastomer modified with anunsaturated carboxylic acid or derivative. The thermoplastic elastomeris a copolymer that is free of halogen. The thermoplastic elastomer ispreferably a block copolymer including styrene polymer segments servingas hard segments and a rubbery polymer segment serving as soft segments.The thermoplastic elastomer thus has, in its molecular structure, thehard segment which functions in a manner similar to a cross-linkingpoint and the soft segment having rubber-like elasticity at ambienttemperature (25° C.). Thus, when the thermoplastic elastomer is heated,it is softened and plastically deformable by an external force (since itis not cross-linked) but is elastomeric at ambient temperature (e.g.15-25° C.).

[0036] In various exemplary embodiments, the hard segment includespolystyrene, poly o-methylstyrene, poly m-methylstyrene, polyp-methylstyrene, poly á-methylstyrene, poly â-methylstyrene,polydimethylstyrene or polytrimethylstyrene. In various exemplaryembodiments, the soft segment includes polybutadiene, anethylene-propylene copolymer, an ethylene-propylene-dienetri-dimensional copolymer, polyisoprene, or a butadiene-isoprenecopolymer. It is possible to use these styrene thermoplastic elastomersalone or in combination.

[0037] As the styrene thermoplastic elastomer, a styrene-butadiene blockcopolymer, a styrene/ethylene-propylene block copolymer and astyrene/ethylene butadiene block copolymer are preferred.

[0038] To improve the heat resistance of the resin composition, it ispreferable to use a hydrogenated styrene thermoplastic elastomer havingdouble bonds in its molecular chain saturated by hydrogen. Inparticular, a hydrogenated styrene/ethylene-propylene block copolymerand a hydrogenated styrene/butadiene block copolymer are preferred.

[0039] Subsequent to polymerization and hydrogenation, the thermoplasticelastomer is allowed to react with the unsaturated carboxylic acid orits derivative to form the modified styrene thermoplastic elastomer.

[0040] In various exemplary embodiments, unsaturated carboxylic acidswhich are used to modify the styrene thermoplastic elastomer can includemaleic acid, fumaric acid, itaconic acid, acrylic acid, and the like.Derivatives of unsaturated carboxylic acids include maleic anhydride,monoester maleate, diester maleate, fumaric anhydride, monoesterfumarate, diester fumarate, itaconic anhydride, monoester itaconate,diester itaconate, and the like. Of these derivatives, maleic anhydrideis preferred. Modification with maleic anhydride improves mechanicalcharacteristics, such as wear resistance, of the resin composition.

[0041] It is preferable that the modification ratio of the modifiedstyrene thermoplastic elastomer is from about 0.1 to about 10 wt %(weight of modifying unsaturated carboxylic acid or derivative). If themodification ratio is less than about 0.1 wt %, the chemical bondingstrength of the thermoplastic elastomer to the surface of the metalhydroxide decreases, and thus a strong bonding interface cannot beobtained. Thus, the effect obtained by the modification is liable to besmall. If the modification ratio is more than about 10 wt %, the variouscharacteristics of the resin composition do not balance well with oneanother.

[0042] In various exemplary embodiments, the metal hydroxide of thisinvention includes magnesium hydroxide, aluminum hydroxide or calciumhydroxide. Magnesium hydroxide is most preferred because itsdecomposition temperature is as high as about 360° C. It is preferablethat the average particle diameter of the metal hydroxide is from about0.1 μm to about 20 μm to improve the mechanical characteristics, such aswear resistance, of the composition. In various exemplary embodiments,the resin composition of this invention is free from fibrous fillers. Invarious exemplary embodiments, the metal hydroxide or combination ofmetal hydroxide is the only filler present in the resin composition.

[0043] To enhance the dispersibility of the metal hydroxide in thepolymer and its reactivity with the polymer, the particles of the metalhydroxide may be surface-treated with a silane coupling agent such asaminosilane, vinylsilane, epoxysilane or methacryloxysilane or with ahigher fatty acids such as stearic acid or oleic acid.

[0044] The components of the resin composition according to thisinvention can be combined by mixing and kneading by conventional methodsthat permit adjustment of the mixing ratio. In various exemplaryembodiments, the main components (i.e., the two synthetic resins and themetal hydroxide) are mixed and kneaded together simultaneously, in asingle-step mixing process. In various other embodiments, the modifiedstyrene-based resin is mixed with the metal hydroxide first, and thenthe propylene resin is added. In various exemplary embodiments, thestyrene-based resin is modified with the unsaturated carboxylic acid orderivative thereof prior to mixing the styrene-based resin with theother two main components. Thus, the modified styrene-based resin ismixed with the metal hydroxide in a state in which the unsaturatedcarboxylic acid (or derivative) modifying group has not reacted withanother compound.

[0045] It has been found that the modified styrene-based polymer has ahigh affinity for the hydroxide due to the presence of the carboxylicacid or derivative thereof. Therefore the modified styrene-based resinmore easily adheres to the hydroxide particles than the propylenepolymer. A morphology is thus achieved in which the styrene-basedpolymer coats the filler particles and the propylene polymer fills thespace between the coated filler particles. In this “spotted” or “island”structure, the propylene polymer is in a “continuous phase” and thecoated filler particles are in a “discontinuous phase.” This morphologyis illustrated by micrographs of the resin composition, described laterwith reference to the Examples.

[0046] If the mixing ratio of the propylene resin is less than about 60parts by weight, the wear resistance of the composition tends to be low.If the mixing ratio of the propylene resin is more than about 97 partsby weight, the flexibility and processability of the composition tend tobe low. If the mixing ratio of the modified styrene thermoplasticelastomer is less than about three parts by weight, the flexibility andprocessability of the composition tend to be low. If the mixing ratio ofthe modified styrene thermoplastic elastomer is more than about 40 partsby weight, the wear resistance of the composition tends to be low.

[0047] If the mixing ratio of the metal hydroxide is less than about 30parts by weight per 100 parts by weight of the polymers, the compositionis not sufficiently fire resistant. If the mixing ratio of the metalhydroxide is more than about 200 parts by weight per 100 parts by weightof the polymers, the composition has a low degree of tensile elongation,wear resistance, flexibility, and processability.

[0048] It is preferable that from about 70 to about 90 parts by weightof the propylene resin are mixed with from about 10 to about 30 parts byweight of the styrene thermoplastic elastomer modified with theunsaturated carboxylic acid or its derivative and that from about 50 toabout 150 parts by weight of the metal hydroxide is added to 100 partsby weight of the mixture of the propylene resin and the modified styrenethermoplastic elastomer.

[0049] In various exemplary embodiments, the composition contains otheradditives, provided that the additives do not deteriorate thecharacteristics of the composition. Typical conventional additivesinclude halogen-free antioxidants, metal-inactivating agents such ascopper inhibitors and the like, processing aids such as lubricants,waxes, and the like, colorants and flame retarding additives such aszinc borate and silicon flame retarding additives.

[0050] However, as mentioned above, the composition contains nosynthetic resin component other than the propylene resin and themodified styrene-based thermoplastic elastomeric resin. Furthermore, thecomposition should contain no component, other than the metal hydroxide,which reacts with the unsaturated carboxylic acid or derivative thereofof the modified styrene-based resin. It is desired that the modifiedstyrene-based resin bonds directly to the metal hydroxide, to improvethe mixing and dispersion of the metal hydroxide particles in thecomposition.

[0051] The propylene resin and the modified styrene thermoplasticelastomer are highly compatible with each other, so it is possible toform a uniform composition without damaging the various characteristicsof the modified styrene thermoplastic elastomer. The resin compositionaccording to this invention has good processability and moldabilitybecause the composition achieves a balance between mechanicalcharacteristics and flexibility. Accordingly, the composition hasappropriate hardness and flexibility.

[0052] In embodiments where the composition contains from about 70 toabout 90 parts by weight of the propylene resin mixed with from about 10to about 30 parts by weight of the styrene thermoplastic elastomermodified with the unsaturated carboxylic acid or its derivative and fromabout 50 to about 150 parts by weight of the metal hydroxide per 100parts by weight of the polymers, the composition has improved mechanicalcharacteristics such as wear resistance, tensile strength and tensileelongation. Such a resin composition also achieves an excellent balancebetween these characteristics.

[0053] The covered electrical wire of this invention is obtained bycoating the peripheral surface of a conductor with the above-describedcomposition. The wire may be obtained by applying the composition to theperipheral surface of the conductor concentrically. In various exemplaryembodiments, the conductor includes a plurality of intertwined softcopper wires, in accordance with JIS C 3102, or a plurality of softcopper wires intertwined with each other and circularly compressed.

[0054] Preferably, the conductor is covered with the composition to athickness of from about 0.2 mm to about 0.3 mm. If the coating thicknessis less than about 0.2 mm, the covered wire may suffer from deterioratedwear resistance. If the coating thickness is greater than about 0.3 mm,the covered wire may suffer from deteriorated flexibility.

[0055] In various exemplary embodiments, one or more layers of awater-resistant, halogen-free resin composition are interposed betweenthe fire resistant composition and the conductor.

[0056] To obtain the covered wire according to this invention havingsuperior characteristics, it is necessary to select an optimum mixingratio of the components of the fire resistant composition that isapplied to the conductor as the coating material. The ratio can beselected with consideration for the cross-sectional area of theconductor and the coating thickness of the resin composition.

[0057] For example, when the cross-sectional area of the conductor isfrom about 0.35 mm² to about 1.5 mm² and the coating thickness is about0.2 mm, it is preferable to mix the components of the fire resistantcomposition at the following ratio: about 90 parts by weight of thepropylene resin and about 10 parts by weight of the modified styrenethermoplastic elastomer, with about 70 parts by weight of the metalhydroxide per 100 parts by weight of the polymers.

[0058] When the cross-sectional area of the conductor is from about 0.22mm² to about 1.5 mm² and the coating thickness is from about 0.2 mm toabout 0.3 mm, it is preferable to mix the components of the fireresistant composition at the following ratio: about 80 parts by weightof the propylene resin and about 20 parts by weight of the modifiedstyrene thermoplastic elastomer, with about 90 parts by weight of themetal hydroxide per 100 parts by weight of the polymers.

[0059] When the cross-sectional area of the conductor is more than about1.5 mm² and the coating thickness is more than about 0.2 mm, it ispreferable to mix the components of the composition at the followingratio: from about 60 to about 70 parts by weight of the propylene resinand from about 30 to about 40 parts by weight of the modified styrenethermoplastic elastomer, with from about 70 to about 90 parts by weightof the metal hydroxide per 100 parts by weight of the polymers.

[0060] When the covered wire is narrow, to obtain a satisfactory fireresistance, it is preferable to mix the components of the composition atthe following ratio: from about 65 to about 97 parts by weight of thepropylene resin and from about 3 to about 35 parts by weight of themodified styrene thermoplastic elastomer, with from about 100 to about200 parts by weight of the metal hydroxide per 100 parts by weight ofthe polymers.

[0061] In this case, it is more preferred to mix the components of thecomposition at the following ratio: from about 70 to about 95 parts byweight of the propylene resin and from about 5 to about 30 parts byweight of the modified styrene thermoplastic elastomer, with from about120 to about 180 parts by weight of the metal hydroxide per 100 parts byweight of the polymers.

[0062] When the cross-sectional area of the conductor is about 0.13mm²and the coating thickness is 0.2 mm, it is preferable to mix thecomponents of the composition at the following ratio: about 90 parts byweight of the propylene resin and from about 10 to about 40 parts byweight of the modified styrene thermoplastic elastomer, and about 160parts by weight of the metal hydroxide per 100 parts by weight of thepolymers.

[0063] The electrical wire of the present invention is highly fireresistant and has good mechanical characteristics, flexibility, andprocessability. Furthermore, because a cross-linking process is notrequired in forming the composition, it is unnecessary to usecross-linking equipment in manufacturing the electrical wire. Thus, thenumber of steps in the manufacturing processes is reduced, in turnreducing the cost of manufacture.

[0064] Accordingly, in various exemplary embodiments of the resincomposition of this invention, the composition is free fromcross-linking agents, such as a peroxide. The composition, as applied asa wire covering, can also be free from cross-linking agents. However, ifdesired, cross-linking can be performed, for example, chemically or byelectron beam or ultraviolet irradiation.

[0065] The covered wire according to this invention has goodprocessability. When the end of the coated electric wire is peeled fromthe conductor, a whiskery coating material does not remain on the end ofthe wire. Accordingly, when the conductor is used in combination with acrimping terminal, a whiskery coating does not become sandwiched betweenthe conductor and the crimping terminal. It is thus possible to avoidunwanted resistance. That is, when the covering is peeled from theconductor, the wire remains highly operable.

[0066] To obtain an electrical wire according to this invention havingimproved resistance to whitening upon bending and having goodflexibility, it is preferred that the electrically insulating coveringon the conductor is a composition having a 2% tensile stress of not morethan about 7 MPa. Preferably the 2% tensile strength is at least about 2MPa. It is also preferred that the 300% tensile stress of one of thepolymer components of the composition is not more than about 5 MPa. Inparticular, it is desirable for the styrene-based thermoplasticelastomer to have a 300% tensile stress of not more than about 5 MPa.

[0067] It is preferred that the 2% tensile stress of the polymercomposition is from about 5 to about 7 MPa when the coating thickness isabout 0.2 mm or less, and from about 2 to about 6 MPa when the coatingthickness is from about 0.2 mm to about 0.3 mm. Namely, when the coatingis thinner, the tensile stress of the polymer composition can be chosento be comparatively large, and when the coating is thicker, the tensilestress can be chosen to be comparatively small. When the tensile stressof the polymer composition is selected in this manner, flexibility ofthe coated electric wire is obtained in both thin and thick coatings.

EXAMPLES

[0068] This invention is illustrated by the following Examples, whichare merely for the purpose of illustration and are not to be regarded aslimiting the scope of the invention, or the manner in which it may bepracticed. In the Tables, quantities are given in parts by weight.

[0069] In each of the Examples and Comparative Examples below, thecomponents were continuously mixed and kneaded as follows. The two resincomponents and the metal hydroxide were fed simultaneously into theinput hopper of a twin-shaft extruder having an electrical heatingjacket. This extruder was employed to knead the components together. Theextruder temperature (inner surface) was 200° C. at entry, rising to250° C. at exit. At the exit end there was an extrusion head for formingstrands from the mixed composition. The extrusion head was maintained ata temperature of 260° C. The resulting strands were passed through awater bath to a pelletizer, to form pellets. The pellets were used tomake wire covering, as described below.

Examples 1-10 and Comparative Examples 1-9

[0070] In Examples 1-5 and Comparative Examples 1-5, resin compositionswere prepared by kneading components in the quantities shown in Tables 1and 2, respectively.

[0071] To evaluate the characteristics of each composition, electricalwires were prepared by applying each composition at a thickness of 0.28mm to a conductor (seven soft copper wires twisted together andcircularly compressed to give a smooth peripheral surface) having across-sectional area of 0.5 mm², using an extrusion molding machine. Thedie nipples used in the extrusion molding were 1.40 mm and 0.88 mm indiameter. The extrusion temperature of the die was 210° C. to 230° C.The extrusion temperature of the cylinder was 200° C. to 240° C. Thelinear speed was 50 m/minute.

[0072] In Examples 6-10, resin compositions were prepared by kneadingcomponents in the quantities shown in Table 3. The mixing ratios ofthese compositions were selected to be used preferably in electricalwire having a small diameter.

[0073] In Comparative Examples 6-9, resin compositions were prepared bykneading components in the quantities shown in Table 4.

[0074] To evaluate the characteristics of each of the compositions inExamples 6-10 and Comparative Examples 6-9, electrical wires wereprepared by applying each composition at a thickness of 0.20 mm to aconductor (seven soft copper wires twisted together and circularlycompressed to give a smooth peripheral surface) having a cross-sectionalarea of 0.13 mm², using an extrusion molding machine. The die nipplesused in the extrusion molding were 0.50 mm and 0.90 mm in diameter. Theextrusion temperature of the die was 210° C. to 230° C. The extrusiontemperature of the cylinder was 200° C. to 240° C. The linear speed was50 m/minute.

[0075] The Examples and Comparative Examples were tested to evaluatefire resistance, wear resistance, tensile strength, tensile elongation,flexibility, and processability, as described below.

[0076] A fire resistance test was conducted in accordance with JASOD611-94, of the Japanese Automobile Standards Organization. Electricalwire was cut to a length of 300 mm to prepare a specimen. Each specimenwas put in a test box made of iron and supported horizontally. Using aBunsen burner having a bore of 10 mm, the tip of a reducing flame wasapplied to the underside of the center of each specimen to burn thespecimen for 30 seconds. An after-flame time was measured for eachspecimen. Specimens having an after-flame time of less than 15 secondswere regarded as successful. Specimens having an after-flame time ofmore than 15 seconds were regarded as failures.

[0077] In accordance with JASO OG11-94, a wear resistance test wasconducted by a blade reciprocation method. The covered electrical, wirewas cut to a length of 750 mm to prepare a specimen. At a roomtemperature of 23±5° C., the surface of the coating material of eachspecimen fixed to a table was worn by axially reciprocating a blade at arate of 50 times per minute over a length more than 10 mm. A load of 7Nwas applied by the blade. The number of reciprocations of the blade wasmeasured until the blade contacted the conductor due to the wear of thecoating material.

[0078] Then, each specimen was moved 100 mm and rotated 90 degreesclockwise and the measurement by the above-described method wasrepeated. The test was performed three times on each specimen. InExamples 1-5 and Comparative Examples 1-5, specimens for which the bladereciprocated more than 150 times were regarded as successful. InExamples 6-10 and Comparative Examples 6-10, specimens for which theblade reciprocated more than 100 times were regarded as successful.

[0079] In accordance with JASO D611-94, tensile strength and tensileelongation tests were conducted. Each covered electrical wire was cut toa length of 150 mm to prepare a specimen. The conductor was removed fromthe specimen to form a tubular body. Lines were marked on the center ofthe specimen at intervals of 50 mm. At a room temperature of 23±5° C.the ends of the specimen were mounted on chucks of a tensile testingmachine. Then, the specimen was drawn at a speed of 200 m/minute tomeasure the load and the length between adjacent marked lines when thespecimen was cut (broken). Specimens having a tensile strength of morethan 15.7 MPa and a tensile elongation of more than 125% were regardedas successful.

[0080] To evaluate flexibility, specimens were bent by hand. Thosespecimens giving a good feeling when they were bent by hand wereregarded as successful.

[0081] To test processability, a part of the resin composition disposedat the end of each covered wire was peeled off of the conductor to checkwhether a whisker was formed. Specimens on which no whisker was formedwere admitted as successful.

[0082] The results are shown below in Tables 1-4. TABLE 1 E1 E2 E3 E4 E5P-E polymer A¹ 60 97 80 90 80 MAH-SEBS A² 40 3 20 10 20 Magnesiumhydroxide A³ 70 90 — — 90 Magnesium hydroxide B⁴ — — 50 200 —Antioxidant⁵ 1 1 1 1 1 Total (parts by weight) 171 191 151 301 191 Fireresistance Pass Pass Pass Pass Pass Wear resistance 500 1800 4000 3002000 reciprocation number of blade) Tensile strength (MPa) 28 31 34 2333 Tensile elongation (%) 200 420 520 160 320 Flexibility Good Good GoodGood Good Processability Pass Pass Pass Pass Pass

[0083] TABLE 2 CE1 CE2 CE3 CE4 CE5 P-E polymer A¹ 99 50 70 70 80MAH-SEBS A² 1 50 30 30 — SEBS⁶ — — — — 20 Magnesium hydroxide A³ 70 — 20— 90 Magnesium hydroxide B⁴ — 80 — 250 — Anitoxidant⁵  1 1  1 1  1 Total(parts by weight) 171 181 121 351 191 Fire resistance Pass Pass FailPass Pass Wear resistance 1500 90 1300 75 140 (reciprocation number ofblade) Tensile strength (MPa) 35 20 40 16 37 Tensile elongation (%) 670110 600 80 710 Flexibility Bad Good Good Bad Good Processability FailPass Pass Fail Pass

[0084] TABLE 3 E6 E7 E8 E9 E10 P-E polymer A¹ 95 90 80 65 80 MAH-SEBS A²5 10 20 35 20 Magnesium hydroxide B⁴ 120 150 200 160 100 Anitoxidant⁵ 11 1 1 1 Total (parts by weight) 221 251 301 261 201 Fire resistance PassPass Pass Pass Pass Wear resistance >500 >500 >500 180 >500(reciprocation number of blade) Tensile strength (MPa) 32 30 32 30 19Tensile elongation (%) 260 220 210 250 265 Flexibility Good Good GoodGood Good Processability Pass Pass Pass Pass Pass

[0085] TABLE 4 CE6 CE7 CE8 CE9 P-E polymer A¹ 99 55 70 90 MAH-SEBS A² 145 — 10 SEBS⁶ — — 30 — Magnesium hydroxide B⁴ 160 120 150 220Antioxidant⁵ 1 1 1 1 Total (parts by weight) 261 221 251 321 Fireresistance Pass Pass Pass Pass Wear resistance (reciprocation numberof >500 60 75 >500 blade) Tensile strength (MPa) 33 30 27 33 Tensileelongation (%) 220 280 320 180 Flexibility Bad Good Good BadProcessability Fail Pass Pass Fail

[0086] The coated wire of each of Examples 1-5 of this invention wassatisfactory in fire resistance, wear resistance, tensile strength,tensile elongation, flexibility and process ability. On the other hand,none of the coated wires of Comparative Examples 1-5 providedsatisfactory results for all of the measured characteristics.

[0087] In particular, the resin composition of each of Examples 3 and 5shown in Table 1 had preferable mechanical strength properties such aswear resistance, tensile strength and tensile elongation, and a goodbalance between these characteristics. Each of these compositionscontained 70 to 90 parts by weight of the propylene resin and 10 to 30parts by weight of the styrene thermoplastic elastomer modified with theunsaturated carboxylic acid or its derivative and 50 to 150 parts byweight of the metal hydroxide per 100 parts by weight of the mixture ofthe polymers.

[0088] As shown in Table 2, in the composition of Comparative Example 1,the mixing ratio of the propylene-ethylene block copolymer was high, andthe mixing ratio of the maleic anhydride-modified hydrogenatedstyrene-butadiene-styrene copolymer was low. Thus, this composition hadpoor flexibility and processability. In the composition of ComparativeExample 2, the mixing ratio of the propylene-ethylene block copolymerwas low, and the mixing ratio of the maleic anhydride-modifiedhydrogenated styrene-butadiene-styrene copolymer was high. Thus, thiscomposition had poor tensile elongation and wear resistance.

[0089] In the composition of Comparative Example 3, the mixing ratio ofthe magnesium hydroxide was low. As a result, this composition had poorfire resistance. In the composition of Comparative Example 4, the mixingratio of the magnesium hydroxide was high. As a result, this compositionhad insufficient tensile elongation, and gave poor results inevaluations of wear resistance, flexibility, and processability.

[0090] In the composition of Comparative Example 5, instead of themaleic anhydride-modified hydrogenated styrene-butadiene-styrenecopolymer, the unsaturated hydrogenated styrene-butadiene-styrenecopolymer was used. Thus, a strong bonding interface was not formedbetween the metal hydroxide and the hydrogenatedstyrene-butadiene-styrene copolymer. Consequently, this compositiondemonstrated poor wear resistance.

[0091] The wire of each of Examples 6-10 of this invention wassatisfactory in fire resistance, wear resistance, tensile strength,tensile elongation, flexibility and processability. On the other hand,none of the wires Comparative Examples 6-9 provided satisfactory resultsfor all of the characteristics.

[0092] As shown in Table 4, in the composition of Comparative Example 6,the mixing ratio of the propylene-ethylene block copolymer was high, andthe mixing ratio of the maleic anhydride-modified hydrogenatedstyrene-butadiene-styrene copolymer was low. Thus, this composition gavepoor results in tests of flexibility and processability. In thecomposition of Comparative Example 7, the mixing ratio of thepropylene-ethylene block copolymer was low, and the mixing ratio of themaleic anhydride-modified hydrogenated styrene-butadiene-styrenecopolymer was high. Thus, this composition provided low wear resistance.

[0093] In the composition of Comparative Example 8, instead of themaleic anhydride-modified hydrogenated styrene-butadiene-styrenecopolymer, the unsaturated hydrogenated styrene-butadiene-styrenecopolymer was used. Thus, a strong bonding interface was not formedbetween the metal hydroxide and the hydrogenatedstyrene-butadiene-styrene copolymer. As a result, the compositiondemonstrated poor wear resistance.

[0094] In the composition of Comparative Example 9, the mixing ratio ofthe magnesium hydroxide was high. As a result, this composition providedpoor results in tests of flexibility and processability.

Example 11

[0095] 80 parts by weight of the propylene-ethylene block copolymerdescribed above (MFR=0.5 g/10 min.), 20 parts by weight of the modifiedstyrene-based elastomer described above and 90 parts by weight ofmagnesium hydroxide (untreated) were kneaded with a twin-screw extruderat 250° C. A micrograph of the resulting composition was produced with atransmission electron microscope (TEM) (model H-800 by HITACHI) at anacceleration voltage of 100 KV. The sample was cut to a thickness ofabout 10 μm by a microtome for an electron microscope, and the cutsample was dyed with ruthenic acid (2% aqueous solution) for 2 hours.Then, the dyed sample was mounted in an epoxy resin, and a micrographwas obtained using an ultra thin intercept method. The micrograph isshown in FIG. 1.

[0096] As illustrated by FIG. 1, the approximately hexagonal particleswhich are situated at the central part of the picture and thesurrounding narrow long particles are the particles of magnesiumhydroxide. The dense portion forming a rim around each of theseparticles is the modified styrene-based elastomer that coats theparticles, and the material filling the space between the particles isthe continuous matrix phase of the propylene-ethylene block copolymer.FIG. 1 demonstrates that the filler particles hardly coagulate, and arefinely dispersed in the continuous phase of the propylene-ethylene blockcopolymer.

Comparative Example 10

[0097] A composition was prepared in like manner as in Example 1 exceptthat the unsaturated hydrogenated styrene-butadiene-styrene copolymer,not modified with maleic anhydride, was used in place of the modifiedstyrene-based elastomer. A micrograph was obtained and is shown in FIG.2.

[0098] Comparison of FIGS. 1 and 2 demonstrates that the thisstyrene-based polymer modified by unsaturated carboxylic acid, by reasonof its affinity with the magnesium hydroxide filler particles, forms astructure in the mixture in which it surrounds the particlespreferentially. This is advantageous for obtaining the propertiesdesirable in compositions used in wire covering.

Examples 12 to 21 and Comparative Examples 11 and 12

[0099] In Examples 12-21 and Comparative Examples 11-12, resincompositions were prepared by kneading components in the quantitiesshown in Tables 5 and 6.

[0100] To evaluate the characteristics of each of the compositions inExamples 12-21 and Comparative Examples 11-12, electrical wires wereprepared by applying each composition at a thickness of 0.28 mm to aconductor (seven soft copper wires having a diameter of 0.32 mm twistedtogether and circularly compressed to give a smooth peripheral surface)having a cross-sectional area of 0.5 mm², using an extrusion moldingmachine. The die nipples used in the extrusion molding were 1.40 mm and0.88 mm in diameter. The extrusion temperature of the die was 210° C. to230° C. The extrusion temperature of the cylinder was 200° C. to 240° C.The linear speed was 50 m/minute.

[0101] The flame resistance, wear resistance and tensilestrength/elongation, flexibility and processability were evaluated inthe same manner as above. In evaluating wear resistance, 150 or moreblade reciprocations was regarded as successful. TABLE 5 E12 E13 E14 E15E16 CE11 P-E polymer A¹ 60 97 80 90 80 80 MAH-HSBR⁷ 40 3 20 10 20 —HSBR⁸ — — — — — 20 Magnesium hydroxide³ 70 90 — — 90 80 Magnesiumhydroxide⁴ — — 30 200 — — Antioxidant⁵ 1 1 1 1 1 1 Total 171 191 131 301191 191 Tensile elongation (%) 300 >500 >500 170 >500 >500 TensileStrength (MPa) 27 30 31 24 30 34 Fire Resistance Pass Pass Pass PassPass Pass Wear resistance 400 1500 2500 260 1800 110 (bladereciprocation number) Flexibility Good Good Good Good Good BadProcessability Pass Pass Pass Pass Pass Fail

[0102] TABLE 6 E17 E18 E19 E20 E21 CE12 P-E polymer A¹ 60 97 80 90 80 80MAH-SEPS⁹ 40 3 20 10 20 — SEPS¹⁰ — — — — — 20 Magnesium hydroxide A³ 7090 — — 90 80 Magnesium hydroxide B⁴ — — 30 200 — — Antioxidant⁵ 1 1 1 11 1 Total 171 191 131 301 191 191 Tensile elongation (%) 250 >500 >500170 >500 >500 Tensile Strength (MPa) 25 28 26 27 28 27 Fire ResistancePass Pass Pass Pass Pass Pass Wear resistance 400 1300 1200 260 1700 90(blade reciprocation number) Flexibility Good Good Good Good Good GoodProcessability Pass Pass Pass Pass Pass Pass

Example 22 and Comparative Examples 13 and 14

[0103] In Example 22 and Comparative Examples 13 and 14, resincompositions were prepared by kneading components in the quantitiesshown in Table 7. The obtained composition was extrusion-molded to acoating thickness of 0.28 mm around a conductor having a cross-sectionalarea of 0.5 mm² (7/SB: twisted wire which is composed of seven softcopper wires having a diameter of 0.30 mm). The die nipples used haddiameters of 1.40 mm and 0.88 mm, in the extrusion molding. Theextrusion temperature was 240° C. to 250° C. for the die and 230° C. to250° C. for the cylinder, and the extrusion molding was carried out at alinear velocity of 50 m/min.

[0104] To test for whitening, the obtained coated electrical wire wasbent in a standard manner, and was visually evaluated to determinewhether the coating had whitened or not. Results are shown in Table 1,which also gives the 2% tensile stress of the coating composition.

[0105] The flexibility of the coated electrical wire was evaluated asfollows. An article which was obtained by bundling 30 pieces of thecoated electric wire having a length of 350 mm and roughly winding thebundle with a vinyl tape is made as a sample. The sample was mounted ona pair of cylinders (each having a diameter of 19 mm) which werearranged mutually parallel and spaced horizontally which a gap of 100mm, with the sample perpendicular to the axes of the cylinder so thatthe center of the sample was situated at the center of the gap betweenthe cylinders. The sample was slowly pulled downward at the centerbetween the cylinders at room temperature, and the maximum load bornwhile the sample remained on the cylinders was measured. In the test, amaximum load of 70N or less for a coating thickness of 0.20 mm, and amaximum load of 50N or less for a coating thickness of 0.28 mm, wereregarded as passing. TABLE 7 E22 CE13 CE14 MAH-SEBS 1² 20 MAH-SEBS 2¹¹10 SEBS epoxy¹² 5 P-E Polymer A¹ 80 95 HDPE¹⁴ 90 Magnesium hydroxide B⁴100 100 100 Antioxidant⁵ 1 1 1 2% Tensile stress (MPa) 5.8 7 9 Whiteningon bending No Yes Yes Flexibility Pass Reject Reject

Examples 23 and Comparative Examples 15 and 16

[0106] Components were kneaded by a twin-screw extruder at 250° C., inthe quantities listed in Table 8. The obtained composition wasextrusion-molded to a coating thickness of 0.20 mm or 0.28 mm around aconductor having a cross-sectional area of 0.5 mm² (7/SB: twisted wirewhich is composed of seven soft copper wires having a diameter of 0.30mm). Die nipples in extrusion molding were 1.25 mm and 0.88 mm indiameter for coating thicknesses of 0.20 mm and 1.40 mm and 0.88 mm indiameter for a coating thickness of 0.28 mm. The extrusion temperaturewas 240° C. to 250° C. for the die and 230° C. to 240° C. for thecylinder. The extrusion molding was carried out at a linear velocity of50 m/min.

[0107] Flexibility and whitening were evaluated as described above. Theresults are shown in Table 8. TABLE 8 E23 CE15 CE16 P-E Polymer A⁴ 90 95HDPE¹⁴ 90 MAH-SEBS 1² 10 5 MAH-EPR¹⁶ 10 Magnesium hydroxide B⁴ 80 100100 Antioxidant⁵ 1 1 1 Coating thickness (mm) 0.20 0.20 0.28 2% Tensilestress (MPa) 7.0 9.0 7.3 Whitening on bending No Yes Yes FlexibilityPass Reject Reject

Examples 24 to 33

[0108] In Examples 24 to 28, components were kneaded in the ratios shownin Table 9 to prepare resin compositions.

[0109] To check the characteristics of each composition, using anextrusion molding machine, each composition was applied at a thicknessof 0.28 mm to a conductor (seven soft copper wires twisted together andcircularly compressed to give a smooth peripheral surface) having across-sectional area of 0.5 mm² to prepare an electrical wire. The dienipples used in the extrusion molding were 1.40 mm and 0.88 mm indiameter. The extrusion temperature of the die was 210° C. to 230° C.The extrusion temperature of the cylinder was 200° C. to 240° C. Thelinear speed was 50 m/min.

[0110] In Examples 29 to 33, components were kneaded at the ratios shownin Table 10 to prepare resin compositions. The mixing ratios of thesecompositions were selected to be preferably used in electrical wirehaving a small diameter.

[0111] To check the characteristics of the compositions of Table 10,each composition was applied at a thickness of 0.20 mm to a conductor(seven soft copper wires twisted together and circularly compressed togive a smooth peripheral surface) having a cross-sectional area of 0.13mm², using an extrusion molding machine to prepare the covered wire. Thedie nipples used in the extrusion molding had diameters of 0.50 mm and0.90 mm. The extrusion temperature of the die was 210° C. to 230° C. Theextrusion temperature of the cylinder was 200° C. to 240° C. The linearspeed was 50 m/minute.

[0112] The covered electrical wires of Examples 24 to 33 were tested toevaluate their fire resistance, wear resistance, tensile strength,tensile elongation, flexibility, and processability, as described above.In Examples 24-28, specimens for which the blade reciprocated more than150 times were regarded as successful. In Examples 29-33, specimens forwhich the blade reciprocated more than 100 times were regarded assuccessful.

[0113] Tables 9 and 10 show the components of each resin composition andthe evaluated results for each electrical wire. TABLE 9 E5 E6 E7 E8 E9P-E Polymer A¹ 60 97 80 90 80 MAH-SEBS 1² 40 3 20 10 20 Magnesiumhydroxide A³ 70 90 — — 90 Magnesium hydroxide B⁴ — — 50 200 —Antioxidant⁵  1 1 1 1  1 Total (parts by weight) 171 191 151 301 191Fire resistance Pass Pass Pass Pass Pass Wear resistance (reciprocation500 1800 4000 300 2000 number of blade) Tensile strength (MPa) 28 31 3423 33 Tensile elongation (%) 200 420 520 160 320 Flexibility Good GoodGood Good Good Processability Pass Pass Pass Pass Pass

[0114] TABLE 10 E10 E11 E12 E13 E14 P-E Polymer A¹ 95 90 80 65 80MAH-SEBS 1² 5 10 20 35 20 Magnesium hydroxide B⁴ 120 150 200 160 100 Ageresister⁵ 1 1 1 1 1 Total (parts by weight) 221 251 301 261 201 Fireresistance Pass Pass Pass Pass Pass Wear resistance >500 >500 >500180 >500 (reciprocation number of blade) Tensile strength (MPa) 32 30 3230 29 Tensile elongation (%) 260 220 210 250 265 Flexibility Good GoodGood Good Good Processability Pass Pass Pass Pass Pass

[0115] The coated wire in each of Examples 5 to 14 was thus satisfactoryin fire resistance, wear resistance, tensile strength, tensileelongation, flexibility and processability. In particular, the resincompositions in each of Examples 7 and 9, shown in Table 3, hadpreferable mechanical strength properties such as wear resistance,tensile strength and tensile elongation and a good balance between thesecharacteristics. Each of these compositions contained 70 to 90 parts byweight of the propylene resin and 10 to 30 parts by weight of thestyrene thermoplastic elastomer modified with the unsaturated carboxylicacid or its derivative and 50 to 150 parts by weight of the metalhydroxide per 100 parts by weight of the mixture.

[0116] In summary, according to this invention, an electrical wire isobtained that avoids whitening on bending even when a filler is present,and that has good flexibility.

[0117] This is not limited to the above-described embodiments. It ispossible to make various modifications within the general scope of thisinvention. For example, although the antioxidant was used as an additivein various embodiments, other conventional additives may also be used asappropriate. Exemplary additives include halogen-free antioxidants,metal-inactivating agents (copper inhibitors or the like), processingaids (lubricants, waxes, and the like), colorants, flame retardingagents (zinc borate, silicon flame retarding agents).

[0118] As described above, the resin composition according to thisinvention provides excellent fire resistance without generating halogengas when burned. The resin composition provides good mechanicalcharacteristics including wear resistance, tensile strength, tensileelongation and the like, while also providing good flexibility andprocessability. A superior coated electrical wire can be achieved bycoating a conductor with the resin composition according to thisinvention.

[0119] While this invention has been described in conjunction with thespecific embodiments above, it is evident that many alternatives,combinations, modifications, and variations are apparent to thoseskilled in the art. Accordingly, the exemplary embodiments of thisinvention, as set forth above are intended to be illustrative, and notlimiting. Various changes can be made without departing from the spiritand scope of this invention.

What is claimed is:
 1. A method of making a fire resistant resincomposition comprising mixing together the following components (a), (b)and (c): (a) from about 60 to about 97 parts by weight of a propyleneresin containing propylene as its main monomer component by weight; and(b) from about 3 to about 40 parts by weight of a styrene-basedthermoplastic elastomeric resin modified with an unsaturated carboxylicacid or a derivative of an unsaturated carboxylic acid; and whereincomponents (a) and (b) are free of halogen, and the total amount ofcomponents (a) and (b) is 100 parts by weight and there are no othersynthetic resin components included in the composition, (c) from about30 to about 200 parts by weight of fire resistant metal hydroxide per100 parts by weight of components (a) and (b).
 2. The method of claim 1,wherein component (b) is a styrene-based thermoplastic elastomeric resinmodified with maleic anhydride, and the metal hydroxide is magnesiumhydroxide.
 3. The method of claim 1, wherein component (a) has a meltflow rate of from about 0.1 to about 5 g/10 minutes.
 4. The method ofclaim 1, wherein component (b) is a block copolymer having hard segmentsformed of a monomer selected from styrene and styrene derivatives, andsoft segments having elasticity at ambient temperature.
 5. A method ofmaking a fire resistant resin composition comprising mixing together thefollowing components (a), (b) and (c): (a) from about 80 to about 90parts by weight of a propylene resin containing propylene as its mainmonomer component by weight; and (b) from about 10 to about 20 parts byweight of a styrene-based thermoplastic elastomeric resin modified withmaleic anhydride; wherein components (a) and (b) are free of halogen,the total amount of components (a) and (b) is 100 parts by weight andthere are no other synthetic resin components included in thecomposition, the composition further comprising: (c) from about 70 toabout 90 parts by weight of magnesium hydroxide per 100 parts by weightof components (a) and (b).
 6. The method of claim 5, wherein thepropylene resin is selected from the group consisting of a propylenehomopolymer, an ethylene-propylene block copolymer and anethylene-propylene random copolymer.
 7. The method of claim 5, whereinthe styrene-based thermoplastic elastomeric resin is astyrene/ethylene-butylene/styrene block copolymer modified with maleicanhydride.
 8. The method claim 5, wherein the magnesium hydroxide hasnot been subjected to a surface treatment.
 9. The method of claim 5,wherein the fire resistant resin consists essentially of (a), (b) and(c).
 10. The method of claim 1, wherein the propylene resin has a meltflow rate in the range of from about 0.1 to about 5 g/10 minutes at atemperature of 230° C. and a load of about 2.16 kg.
 11. The method ofclaim 1, wherein components (a), (b) and (c) are mixed togethersimultaneously, in a single-step mixing process.
 12. The method of claim1, wherein components (b) and (c) are mixed together and then component(a) is added.
 13. The method of claim 1, wherein the styrene-basedthermoplastic elastomeric resin is modified with the unsaturatedcarboxylic acid or the derivative of a carboxylic acid prior to mixingwith component (c).
 14. The method of claim 1, wherein the styrene-basedthermoplastic elastomeric resin bonds directly to the fire resistantmetal hydroxide.
 15. The method of claim 1, wherein the styrene-basedthermoplastic elastomeric resin is formed from a styrene thermoplasticelastomer selected from the group consisting of: styrene-butadiene blockcopolymer, styrene/ethylene-propylene block copolymer, andstyrene/ethylene butadiene block copolymer.
 16. The method of claim 15,wherein the styrene thermoplastic elastomer is hydrogenated.
 17. Themethod of claim 1, wherein the modified styrene-based thermoplasticelastomeric resin has a modification ratio of from about 0.1 to about 10wt %.
 18. The method of claim 1, wherein the average particle diameterof the metal hydroxide is from about 0.1 μm to about 20 μm.
 19. Themethod of claim 1, wherein the fire resistant resin composition is freefrom fibrous fillers.
 20. The method of claim 1, wherein the metalhydroxide is the only filler.